1. Field of the Invention
The present invention relates to particle smoke generators and methods of generating particle smoke. More particularly, it relates to a gas turbine exhaust apparatus and a method for disseminating particulates and fibers into the atmosphere to form an obscurant such as a smoke screen.
2. Description of the Prior Art
There are many applications, particularly in the military, wherein it is necessary to generate in the atmosphere an obscurant such as a smoke screen or the like. A prior art smoke generator that employs liquid smoke material, such as fog oil, is disclosed in U.S. Statutory Invention Registration Reg. Number: H765, published Apr. 3, 1990. Conventional particulate smoke generators normally create obscurants by dispersing appropriate quantities of particulate materials, such as EA5763 and EA5768, into the atmosphere to generate smoke.
More specifically, prior art particle smoke generators typically include a small gas turbine having a compressor for drawing fresh air into a combustion chamber where fuel is burned. Also included is a bladed rotor that is rotated by the expanding combustion gases. Such turbines, under normal operating conditions, can discharge a high volume of high-velocity exhaust gases at a temperature of about 500 degrees Fahrenheit. However, such exhaust gases are not directly capable themselves of dispersing a sufficient number of particles into the atmosphere to create an acceptable obscurant. In order to disperse the required density of particles to form an obscurant, modifications to existing turbine systems are often necessary.
Such modified prior art turbine systems usually include a means to bleed off some of the compressor air with a control valve and direct it into an ejector. A low-pressure region is created by the ejector. Particles are transported into the low-pressure region where they are injected into the atmosphere in low volumes via a high-velocity air stream. In some cases the high-velocity air stream is also directed toward the exhaust gases to provide additional particle dispersion and buoyancy.
One of the most critical problems confronting designers of particle smoke generators has been developing the various modifications necessary to convert the many different types of available turbines. Although there are a number of different types of gas turbines commercially available and although the military inventory includes yet a further variety of such turbines, most of these devices do not include a bleed-control valve to provide the required low-pressure region. In most cases, complicated gas-turbine modifications are required to install such control valves and other associated control components. Also, due to the design integrity of many turbines, such modifications are often difficult to perform, because implementing such modifications would cause the overall performance of the turbine to be compromised.
Although there has been a long-recognized need for a convenient and reliable means of converting different types of conventional gas turbines into particle smoke generators, no practical system for doing so has yet been devised. The present invention fulfills this need.